I would obviously pay them if/once the idea took off, but I don't have the capital to do so now.
I 've worked with multiple startups before and they all have the same issue..
Your idea, no matter what it is , is still useful so long as you have the passion and insight to make it true. You just need to put it in the right business frame.
If you can show your idea is worthful , with solid some financial forecast and cash flows, you can go and have the right funding from venture capital. Besides, there are other incubators that can help you , give some funding , and even legal assistance , workplace ....etc.
Still, you can go for a small loan , and have some outsource work to make your beta version / proof of concept for a cheap price that can help you raise funds for your next level..